Rory McIlroy emerged victorious after a tense tussle with Patrick Reed in the last round of the Dubai Desert Classic.

Northern Irishman McIlroy led the field by three shots overnight but Reed (65) picked up six shots in his first 11 holes to wipe out that advantage.

McIlroy responded with three birdies and, after Reed birdied 18 to draw level, holed a 20-footer to win.

Heavy rain caused sufficient delays to force play into a fifth day in Dubai. And the ending could not have been better scripted for the DP World Tour with McIlroy holding off LIV Golf’s Reed on a first Monday finish in 35 years at the Emirates Golf Club’s Majlis course.

“Mentally it was very tough,” McIlroy told BBC Sport, referring to his rivalry with Reed. “I felt like I could have let my emotions get in the way of what I was trying to do because of who was up there on the leaderboard.

“I expended a lot of mental energy just trying to focus on myself.

“I’m going to enjoy this. This is probably sweeter than it should be or needs to be.”

It was the latest instalment of an ongoing rivalry that intensified earlier in the week when McIlroy ignored Reed on the driving range and the American responded by flicking a LIV Golf tee in his direction.

McIlroy then explained why he had rejected Reed’s attempt to strike up a conversation.

“I was subpoenaed by his lawyer on Christmas Eve,” said the 33-year-old, who has been called as a witness in Reed’s defamation case against the PGA Tour among others.

It set the tone for the week with fans keen to see McIlroy and Reed paired together at some point. But while that did not happen, the drama on the final day did not disappoint.

Reed, who was in the penultimate group and started four shots behind McIlroy, quickly ate into that lead with three birdies in his opening six holes, while McIlroy was scrambling pars.

The Northern Irishman then birdied the ninth, 10th and 13th to keep pace with Reed, who eagled the par-five 10th and picked up two more birdies on the 11th and 13th.

They were level on 18 under after 14 holes, and McIlroy blinked first. He missed the green on the short 15th and failed to get up and down for par, dropping his first shot of the round.

However, up ahead Reed had problems after a wayward drive on the par-four 16th. He chipped sideways out of trouble but took three more from there to drop his first shot of the day.

Another errant drive on the par-four 17th cost Reed the chance of making a birdie and McIlroy moved one clear by almost driving the green and then two-putting from the front edge.

Reed drew level with a birdie on the last, watched by McIlroy who was back down the fairway deliberating whether to take on the lake that protects the front of the green, after narrowly avoiding water with his drive.

Mindful of the fact he had hit balls into the water both on Sunday and in the final round last year, McIlroy chose the safer option. He then hit a solid wedge shot in and let out a tremendous roar after holing the birdie putt.

“I was in two minds but with what happened yesterday and last year, I wanted to go wedge and give myself an opportunity,” he said, after claiming his third Dubai Desert Classic title.

“It was nice to be able to play the percentages and for it pay off. It’s a great start to the year.”

Australia’s Lucas Herbert closed with a six-under 66 to finish third on 16 under.

England’s Ian Poulter, who also now plays on the LIV Golf circuit, had a good opportunity to join Herbert on that mark but dunked his third shot into the water on the par-five last, after laying up short of the lake with his second. That led to a scruffy double-bogey finish and 13 under overall.

Sweden’s Henrik Stenson, who gave up the European Ryder Cup captaincy to join LIV Golf, hit the lowest round of the day, an eight-under 64 to climb to 12 under.

Legal proceedings to determine if 13 LIV players can continue to play on the European-based DP World Tour are scheduled to take place in London from 6 to 10 February.